#include <iostream>
#include <vector>
using namespace std;

inline long long mod(long long a, long long m) {
    return (a % m + m) % m;
}

// 拡張 Euclid の互除法
long long extGCD(long long a, long long b, long long &p, long long &q) {
    if (b == 0) { p = 1; q = 0; return a; }
    long long d = extGCD(b, a%b, q, p);
    q -= a/b * p;
    return d;
}

// 答えを x ≡ r (mod. M) として、{r, M} をリターン, 存在しない場合は {0, -1} をリターン
pair<long long, long long> ChineseRem(const vector<long long> &b, const vector<long long> &m) {
    long long r = 0, M = 1;
    for (int i = 0; i < (int)b.size(); ++i) {
        long long p, q;
        long long d = extGCD(M, m[i], p, q); // p is inv of M/d (mod. m[i]/d)
        if ((b[i] - r) % d != 0) return make_pair(0, -1);
        long long tmp = (b[i] - r) / d * p % (m[i]/d);
        r += M * tmp;
        M *= m[i]/d;
    }
    return make_pair(mod(r, M), M);
}

int main() {
    vector<long long> b(3), m(3);
    bool exist_non_zero = false;
    for (int i = 0; i < 3; ++i) {
        cin >> b[i] >> m[i];
        if (b[i]) exist_non_zero = true;
    }

    pair<long long, long long> res = ChineseRem(b, m);
    if (res.second == -1) cout << -1 << endl;
    else if (exist_non_zero) cout << res.first << endl;
    else cout << res.second << endl;
}